I have a 1991 Chevy Caprice that I just got from my grandma. It used to be an old police car and has a lot of miles on it. (210,000). Just the other day it started chugging only when accelerating between 45 mph - 60 mph. I had seen somewhere else online that it could be coils. I was just wondering if you had any more insite before I commit to anything. Thanks for your help in advance.

Given it's age, I'd start with the standard tune-up stuff. Plugs, cap/rotor, air filter, fuel filter, spark plug wires etc....

Do you have a Check Engine Light or Service Engine Soon light on at all?

No, it isn't throwing any codes.

My 1990 Caprice is doing something simmular. Car was running very poorly. Just about every thing has been replaced. sensors, tune up, fuel pump could not figure it out so I took it in and the third mechanic and $596 later I had new injectors. Now At about 65 or so it will chugg or backfire through the TBI and will stop if I down shift into Drive, but a good amount of acceleration will result in more "chugging". . Took it in for one thing and now this chugging started. 194,000 mi good compression.
@ the end of my rope...

Check the govenor connection at the tbi cam when messed up it will be in overdrive to soon and rpm will be to low + it will take out your tranny.